1. Technical Field
The invention refers to a mechanical switching apparatus with a housing containing a retainer supporting a ball which has a control lever projecting radially from it on the input side and said lever is rigidly fixed so that, together with the ball, two rotational movements can be made along axes which are perpendicular to each other and pass through the mid-point of the ball. Such mechanical switching apparatus is used, for example, to switch gearboxes in construction plant, in particular wheel loaders, excavators, and similar equipment. Such construction plant and associated vehicles have gearboxes for driving and operating which possess several forward and several reverse gears so that the operator must have the possibility of, first of all, being able to select the general direction of travel, forwards or backwards, in order that, from this first position, for example in forward travel, he/she is then able to select the appropriate forward gear by changing up or down without there being the danger that a reverse gear is accidentally selected during this procedure.
2. Description of the Prior Art
A mechanical switching apparatus of the above-mentioned type is also known for private vehicle applications for tilting the external mirror about its two swivelling axes to enable the external mirror to be adjusted to the desired spatial angle. In this case the switching apparatus has a housing containing a retainer supporting a ball which can swivel or rotate in all directions. A control lever is rigidly connected to the ball, whereby the possibilities for movement of the control lever and therewith the ball too, are limited by a shift gate corresponding to its construction. With this known switching apparatus for adjusting the external mirror, the control lever can be swivelled from a neutral middle position into two planes perpendicular to each other which intersect at the axis of the control lever. Four individual positions can be attained in order to bring about the four movements necessary for the external mirror. Here, the two positions in each of the two planes are allocated opposing movements. In order to finally cause the appropriate swivel movement of the external mirror, electrical contacts are located in the area of the control lever and, therewith, the housing which are actuated by the control lever in the respective swivel position. The electrical contacts can be provided on the side of the control lever where this projects radially from the ball. However, it is also possible to provide an extension piece on the other side of the ball, in line with the axis of the control lever, which in turn, actuates the four switch contacts concerned. A disadvantage of this switching apparatus is that the electrical switch contacts are located in the immediate vicinity of the control lever and thus within the housing for the mechanical switching apparatus. Therefore, the electrical switch contacts are not separated from the mechanical parts of the switching apparatus. If the gear shift gate is, for example, in the shape of a cross, then each of the four switching positions can only be reached from the neutral middle position, i.e. it is not possible, for example, with a driving gearbox, to first preselect the general direction of travel, forward or reverse, and then from this position, to select an appropriate different forward or reverse gear.